Research Projects

This report describes the results from a two-year study to develop and evaluate a reliable method to estimate PM10 (particulate matter with an aerodynamic diameter of less than 10 µm) and PM2.5 emissions from paved roads. The study was motivated by two observations:

* Calculations made by the California Air Resources Board (Gaffney et al., 1996) suggest that PM10 emissions from paved roads constitute a major fraction of total primary emissions from urban areas in California. For example, in the Los Angeles South Coast Air Basin, automobile traffic on paved roads generates about 170 tons/day or 30 percent of the total of 640 tons/day of PM10 emissions.
* Currently used methods, described in AP-42, to estimate particulate emissions from paved roads are uncertain (Claiborn et al., 1995; Kantameni et al., 1996; Zimmer et al., 1992). Furthermore, because the emissions model is a purely statistical relationship between measured emission rates and silt loading, it has limited applicability to situations different from those used in its derivation.